The decision depends on available time, existing skills, implementation access, and what the contractor gives up by doing marketing work instead of billable or operational work.
The source uses an electrician earning $150-$250+ per hour and compares that with spending 10 hours a month on SEO. Keep that as an illustrative opportunity-cost example rather than a universal earning assumption. The relevant calculation is your own foregone work, staff capacity, and the complexity of the tasks you would otherwise outsource.
DIY can make sense when the work is straightforward, the business has time to learn, and someone can maintain accurate profile data, useful service content, customer-review requests, and basic measurement. Hiring can make sense when technical diagnosis, content planning, implementation, link evaluation, or multi-location coordination exceeds the team's capacity.
A provider should not be chosen merely because it claims to specialize in trades. Ask who will do the work, what access they need, what you will own, how changes are approved, and what evidence they will report. If the business cannot spare 10+ hours a month, that may strengthen the case for outside help, but it does not remove the need to understand the scope. Any quoted plan should also explain what happens if priorities change within the same 10-hour planning assumption.